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Abstract:

The present invention is directed to methods for harnessing flow-induced
electrostatic energy in a tubular length and using this energy to power
electrical devices (e.g., flowmeters, electrically-actuated valves,
etc.). The present invention is also directed to corresponding systems
through which such methods are implemented.

Claims:

1. A method of powering a device in a tubular length through generation
of electrostatic energy locally to said device, the tubular length
comprising a plurality of tubular segments disposed therewithin and
connected in series along so as to form a well, pipeline, or refinery
tubing, said method comprising the steps of: a) flowing a substantially
non-conductive hydrocarbon-based fluid, as a flowstream, through a
designated tubular segment that is electrically-isolated from adjacent
tubular segments to which it is connected, wherein the non-conductive
hydrocarbon-based fluid has a relative permittivity of between 2 and 40;
b) generating a net, steady-state electrostatic potential between the
flowstream and said designated tubular segment; c) harvesting electrical
energy from the electrostatic potential via a ground electrode in
electrical contact with the flowstream and an electrical lead in
electrical contact with the designated tubular segment; and d) using the
electrical energy harvested in step (c) to power one or more devices
downhole.

2. The method of claim 1, wherein the tubular length is operable for
producing and distributing oil, gas, or combinations thereof.

4. The method of claim 1, wherein the designated tubular segment presents
itself to the flowstream as a coating of a first type.

5. The method of claim 4, wherein the coating of a first type is
substantially non-conductive, and wherein said coating comprises a
material selected from the group consisting of polytetrafluoroethylene
(PTFE), polyamides (Nylon), polyimides, polyvinylchloride, polyolefins,
polyesters, and combinations thereof.

6. The method of claim 1, wherein the designated tubular segment
comprises a rough-textured surface on at least a portion of its interior
surface, wherein the rough-textured surface has an average roughness
(Ra) of between 5 μm and 250 μm.

7. The method of claim 1, wherein the designated tubular segment is
electrically-isolated from adjacent tubular segments to which it is
connected by means of a substantially-insulating coating of a second type
about at least the regions that are in mechanical contact with the
adjacent tubular segments.

8. The method of claim 7, wherein the substantially-insulating coating of
a second type is comprised of a material selected from the group
consisting of polytetrafluoroethylene (PTFE), polyamides (Nylon),
polyimides, polyvinylchloride, polyolefins, polyesters, and combinations
thereof.

9. The method of claim 1, wherein the net, steady-state electrostatic
potential is at least about 0.5 mV and at most about 50 kV.

10. The method of claim 1, wherein the device deriving power from the
harvested electrical energy is selected from the group consisting of one
or more of the following: a pressure sensor, a temperature sensor, a
valve, telemetry electronics, flow meter, fluid sensing device, and
combinations thereof.

11. The method of claim 1, wherein the device draws power from an
electrical storage device that is, in turn, charged by the harvested
electrical energy.

12. A system for powering devices in a tubular length through the
generation of electrostatic energy, said system comprising: a plurality
of tubular segments, wherein said tubular segments are useful in
conveying hydrocarbon-based fluids; a) at least one electrically-isolated
tubular segment that is electrically isolated from any adjoining
segments, wherein said electrically-isolated tubular segment includes a
high friction surface on its interior; b) at least one device-bearing
tubular segment comprising at least one device that can be usefully
employed; c) at least one electrical lead establishing connectivity
between the at least one electrically-isolated tubular segment and the at
least one device-bearing tubular segment; d) a flow of substantially
non-conductive hydrocarbon-based fluid, wherein said flow is directed
through the tubular segments in any direction; e) a ground electrode
extending into the flow, wherein an electrical potential exists between
the flow and the interior of the electrically-isolated tubular segment,
and wherein this electrical potential is harnessed to power at least one
device in the at least one device-bearing tubular segment.

13. The system of claim 12, wherein the electrically-isolated tubular
segment presents itself to the flowstream as a substantially
non-conductive coating comprised of a material selected from the group
consisting of polytetrafluoroethylene (PTFE), polyamides (Nylon),
polyimides, polyvinylchloride, polyolefins, polyesters, and combinations
thereof.

14. The system of claim 12, wherein electrically-isolated tubular segment
comprises a high friction surface having an average roughness (Ra)
of between 5 μm and 250 μm.

15. The system of claim 1312 wherein the at least one device-bearing
tubular segment comprises one or more devices selected from the group
consisting of pressure sensors, temperature sensors, valves, telemetry
electronics, flow meters, fluid sensing devices, and combinations
thereof.

16. The system of claim 12, wherein the flow of substantially
non-conductive hydrocarbon-based fluid comprises a fluid selected from
the group consisting of heptanes, diesel, crude oil, mineral oil, and
combinations thereof.

17. The system of claim 12, wherein the flow of substantially
non-conductive hydrocarbon-based fluid possesses a flow rate of between
about 1 liter/minute to about 5,000 liters/minute.

Description:

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application is a continuation-in-part application of
U.S. patent application Ser. No. 13/094,954, entitled "Flow-Induced
Electrostatic Power Generator For Downhole Use In Oil And Gas Wells" and
filed on Apr. 27, 2011, the entire disclosure of which is hereby fully
incorporated herein by reference.

TECHNICAL FIELD

[0002] The present application relates generally to methods and systems
for harnessing electrostatic energy. More particularly, the present
application relates to utilizing flow-induced electrostatic energy to
power electrical devices in the energy industry.

BACKGROUND

[0003] The energy industry has significant electrical power needs in all
divisions of its business, including wells, pipelines, and refineries.
Pumps, valves, sensors, and the like--all require power to function. This
power can be consumed continuously and/or in discrete intervals. For
instance, this power is typically supplied to a downhole well environment
via tubing encapsulated cable (from the surface) or in situ via
batteries. Similarly, devices in other sectors have like means of power
delivery to remote equipment that include cables or batteries local to
devices. Unfortunately, either scenario requires the frequent insertion
and removal of equipment from a remote location such as the sea floor,
well, or remote desolate pipeline which, in turn, leads to a reduction in
efficiency.

[0004] Regarding above-mentioned cabled power scenarios, there are
significant reliability concerns--particularly around the breakage of
long lengths of cable. In a downhole well environment cables require
holes in the packers, which can correspondingly decrease the pressure
rating of any such packer through which they pass. Similarly, paths to
remote locations via cable cause increase complexity and lower
reliability of remote power systems.

[0005] In terms of such above-mentioned battery-powered scenarios,
batteries utilized for such purposes will invariably have a finite life,
thereby requiring intervention when they fail. Associated intervention
costs and protocols would typically entail utilizing appropriate tools to
change out the batteries, which in turn would likely result in lost
production time (i.e., production would likely have to be halted).
Downtime is a cross-function to other energy sector applications,
decreasing the overall system efficiency.

[0006] In view of the foregoing, new methods and/or systems by which
electrical power can be generated (and used) in remote locations would be
extremely useful--particularly wherein it reduces the frequency in which
equipment is replaced at the remote location.

SUMMARY OF THE INVENTION

[0007] The present application is directed to processes (i.e., methods,
the two terms being used interchangeably herein) for harnessing
flow-induced electrostatic energy in an oil and/or gas well, pipeline
(above or subsea), or refineries and using this energy to power
electrical devices (e.g., flowmeters, electrically-actuated valves,
sliding sleeves, etc.) in a remote location (i.e., in the well, at depth,
remote locations within a refinery, desolate and remote areas over long
lengths of a pipeline). The present application is also directed to
corresponding systems through which such methods are (or can be)
implemented. Methods and systems will each be generally characterized as
being of either a first type or a second type, depending upon how the
electrostatic energy is developed within the location.

[0008] In some embodiments, the present invention is directed to methods
(of a first type) of powering devices in a remote location through the
generation of electrostatic energy comprising a plurality of tubular
segments disposed therewithin and connected in series along the well
length, said method comprising the steps of: (a) flowing a substantially
non-conductive hydrocarbon-based fluid, as a flowstream, through a
designated tubular length that is electrically-isolated from adjacent
tubular segments to which it is connected, wherein the non-conductive
hydrocarbon-based fluid has a relative permittivity of between 2 and 40;
(b) generating a net, steady-state electrostatic potential between the
flowstream and said designated tubular length; (c) harvesting electrical
energy from the electrostatic potential via a ground electrode in
electrical contact with the flowstream and an electrical lead in
electrical contact with the designated tubular length; and (d) using the
electrical energy harvested in Step (c) to power one or more devices in a
remote location.

[0009] In some embodiments, the present invention is directed toward
systems of a first type, such systems being operable for powering devices
in a remote location through the generation of electrostatic energy
locally to the device and generally comprising: a plurality of tubular
segments, wherein said tubular segments are useful in conveying
hydrocarbon-based fluids out of said tubular segments; at least one
electrically-isolated tubular segment that is electrically isolated from
any adjoining segments (e.g., via insulation or electrically-insulating
surface coatings), wherein said electrically-isolated tubular segment
includes a high friction surface on its interior; at least one
device-bearing tubular segment comprising at least one device that can be
usefully employed downhole or in a remote area; at least one electrical
lead establishing connectivity between the at least one
electrically-isolated tubular segment and the at least one device-bearing
tubular segment; a flow of substantially non-conductive hydrocarbon-based
fluid, wherein said flow is directed through the tubular segments in a
downstream direction of flow; a ground electrode extending into the flow,
wherein an electrical potential exists between the flow and the interior
of the electrically-isolated tubular segment, and wherein this electrical
potential is harnessed to power at least one device in the at least one
device-bearing tubular segment.

[0010] In some embodiments the present invention is directed to methods
(of a second type) of powering devices in a remote location through the
generation of electrostatic energy locally to the device, said methods
generally comprising the steps of: (a') flowing a substantially
non-conductive hydrocarbon-based fluid, as a flowstream, through a
substantially insulating membrane; (b') generating a net, steady-state
electrostatic potential between the flowstream and said membrane, wherein
the membrane comprises a plurality of flow channels through which the
substantially non-conductive hydrocarbon-based fluid can pass, and
wherein at least a majority of said flow channels have an effective
diameter of at least about 500 nm and at most about 200 μm; (c')
harvesting electrical energy from the electrostatic potential via a
ground electrode in electrical contact with the flowstream and an
electrical lead in electrical contact with the membrane; and (d') using
the electrical energy harvested in Step (c') to power one or more devices
downhole.

[0011] In some embodiments, the present invention is directed to systems
of a second type for powering devices in a remote location through the
generation of electrostatic energy downhole, wherein such systems (of a
second type) generally comprise the following: a plurality of tubular
segments disposed within the wellbore, wherein said tubular segments are
useful in conveying hydrocarbon-based fluids out of said tubular
segments; at least one membrane-bearing tubular segment comprising: (i)
an electrically-grounded outer upstream membrane electrode, (ii) an inner
downstream membrane electrode, (iii) a dielectric filter membrane,
comprising flow channels, disposed between the inner and outer membrane
electrodes wherein at least a majority of said flow channels have an
effective diameter of at least about 500 nm and at most about 200 μm;
at least one device-bearing tubular segment comprising at least one
device that can be usefully employed downhole; at least one electrical
lead establishing connectivity between the inner downstream membrane
electrode and the at least one device-bearing tubular segment; a flow of
substantially non-conductive hydrocarbon-based fluid, wherein said flow
is directed through the tubular segments in a downstream direction of
flow; wherein an electrical potential exists between the
electrically-grounded outer upstream membrane electrode and the inner
downstream membrane electrode, and wherein this electrical potential is
harnessed to power at least one device in the at least one device-bearing
tubular segment.

[0012] In some embodiments, methods and/or systems of either a first or
second type are further coupled with a wireless communication subsystem
(or a step of wirelessly communicating) for wirelessly conveying, to the
surface, data obtained by the devices being wirelessly powered by
harnessed electrostatic energy, as described above.

[0013] The foregoing has outlined rather broadly the features of the
present invention in order that the detailed description of the invention
that follows may be better understood. Additional features and advantages
of the invention will be described hereinafter which form the subject of
the claims of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] For a more complete understanding of the present invention, and the
advantages thereof, reference is now made to the following descriptions
taken in conjunction with the accompanying drawings, in which:

[0015] FIG. 1 illustrates, in flow diagram form, methods of a first type
for generating electrostatic energy in a remote location for the purpose
of powering devices in a petroleum well, pipeline, refinery, or other
applications within the energy industry, in accordance with some
embodiments of the present invention;

[0016] FIG. 2A depicts an electrically-isolated tubular segment of a
system of a first type for generating electrostatic energy in a remote
location for the purpose of powering devices in a petroleum well,
pipeline, refinery or other applications within the energy industry, in
accordance with some embodiments of the present invention;

[0017] FIG. 2B depicts how the electrically-isolated tubular segment shown
in FIG. 2A can be integrated with a system of a first type, in accordance
with some embodiments of the present invention;

[0018] FIG. 3 illustrates, in flow diagram form, methods of a second type
for generating electrostatic energy in a remote location for the purpose
of powering devices in a petroleum well, pipeline, refinery, or other
applications within the energy industry, in accordance with some
embodiments of the present invention;

[0019] FIG. 4A depicts a portion of a membrane-bearing tubular segment of
a system of a second type for generating electrostatic energy in a remote
location for the purpose of powering devices in a petroleum well,
pipeline, refinery, or other applications within the energy industry, in
accordance with some embodiments of the present invention; and

[0020] FIG. 4B depicts how the membrane-bearing tubular segment shown in
FIG. 4A can be integrated with a system of a second type, in accordance
with some embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

1. Introduction

[0021] As mentioned in the foregoing section, the present application is
directed to processes (i.e., methods) for harnessing flow-induced
electrostatic energy in a tubular segment in a remote location and
utilizing this energy to power electrical devices locally (i.e., in the
wellbore, pipeline, refinery, or other applications within the energy
industry). The present application is also directed to corresponding or
otherwise associated systems through which such methods are implemented.
Methods and systems will generally be characterized as being of either a
first type or a second type, the details of which are described below.

2. Methods of a First Type

[0022] With reference to FIG. 1, in some embodiments the present invention
is directed to one or more methods of powering devices in tubular
segments in a remote location through the generation of electrostatic
energy locally to the device, comprising a plurality of tubular segments
disposed therewithin and connected in series along a length, said method
comprising the steps of: (Step 101) flowing a substantially
non-conductive hydrocarbon-based fluid, as a flowstream, through a
designated tubular length that is electrically-isolated from adjacent
tubular segments to which it is connected (either in series or in
parallel), wherein the non-conductive hydrocarbon-based fluid has a
relative permittivity of between 2 and 40; (Step 102) generating a net,
steady-state electrostatic potential between the flowstream and said
designated tubular length; (Step 103) harvesting electrical energy from
the electrostatic potential via a ground electrode (typically in the path
of the flowstream) in electrical contact with the flowstream and an
electrical lead in electrical contact with the designated tubular length;
and (Step 104) using the electrical energy harvested in Step 103 to power
one or more devices. Depending on the embodiment, the tubular segments
may comprise joints, coiled tubing, or combinations thereof.

[0023] Generally, in such above-described method embodiments, the tubular
segment is operable for producing and distributing hydrocarbons (oil,
gas, or combinations thereof) from the subsurface, and this production of
hydrocarbons can take place on either land or offshore (incl. >200
meters deep waters, referred to herein as "deepwater") or the
transportation of hydrocarbons within a refinery. Additionally, such
tubular segments can be of a variety of types including, but not limited
to, vertical and/or deviated wells, cased and/or open-hole wells,
multilateral wells, pipelines on land, pipelines subsea, pipes in a
refinery, pipes on platforms, and combinations of any or all of the
foregoing.

[0024] In some such above-described embodiments, the substantially
non-conductive hydrocarbon-based fluid is a completion fluid, although
drilling fluids, workover fluids, and produced fluids can be similarly
utilized (vide infra). Non-conductive hydrocarbon-based completion fluids
are known in the art. By way of illustration and not limitation, examples
of non-conductive hydrocarbon-based completion fluids can be found in
Pasquier et al., U.S. Pat. No. 7,858,564, issued Dec. 28, 2010; and Patel
et al., U.S. Pat. No. 5,189,012, issued on Feb. 23, 1993.

[0025] In some such embodiments, the substantially non-conductive
hydrocarbon-based fluid is selected from the group consisting of (a) an
injected fluid, (b) a produced fluid, and (c) combinations thereof. By
way of illustration and not limitation, examples of non-conductive
hydrocarbon-based injection fluids can be found in Patton et al., U.S.
Pat. No. 3,301,327, issued Jan. 31, 1967. Produced fluids would naturally
be the oil and/or gas being extracted from the reservoir, and perhaps
comprising amounts of injection fluid (if such fluid was used). In
enhanced oil recovery (EOR) operations, it is contemplated that
electrostatic energy could be produced, and subsequently harnessed,
during either or both of injection and production operations. Fluids may
also comprise of refined hydrocarbon products such as gasoline, kerosene,
lubricating oil, diesel, naphtha, fuel oils, paraffin wax, asphalt, tar,
petroleum coke, liquefied petroleum gas, liquefied natural gas, and
others.

[0026] In some such embodiments, the non-conductive hydrocarbon-based
flowstream flows past the designated tubular length in a direction
parallel to the path the tubular segment. In a well, such flowstreams
naturally can be directed toward the surface or away from it, depending
upon whether the flowstream comprises a produced fluid or an injection
fluid. In some "huff-n-puff" enhanced oil recovery (EOR) applications,
the flowstream can be cycled in both directions in the same well.
Otherwise, the flowstream can be directed upstream or downstream of
conventional flow of the tubular segment design.

[0027] In some such above-described method embodiments, the non-conductive
hydrocarbon-based flowstream flows past the designated tubular length in
a side-pocket mandrel assembly providing for a diverted flowpath. In such
embodiments, the diverted flow can be used to generate electrostatic
energy, while not impeding flow (or offering only minimal fluid flow
impedance) of fluids in the primary conduit through which they are
transported. See Crawford et al., U.S. Pat. No. 5,740,860, issued Apr.
21, 1998, for an example of how a side-pocket mandrel can be integrated
with a production string.

[0028] In some embodiments, the designated tubular length presents itself
to the flowstream as a coating of a first type. In some such embodiments,
the coating of a first type is substantially non-conductive. Exemplary
such coating of a first type include, but are not limited to, material
selected from the group consisting of polytetrafluoroethylene (PTFE),
polyamides (Nylon), polyimides, polyvinylchloride (PVC), polyolefins,
polyesters, and combinations thereof. Such coatings can be made with a
range of uniformity and a variety of thicknesses, the latter often being
dependent on the durability of the coating material and/or its
"adhesiveness" to the tubular segment of which it is part. Such coatings
can also be multi-layered.

[0029] In some embodiments, regardless of the material of the coating (if
any), the designated tubular length comprises a rough-textured surface on
at least a portion of its interior surface, wherein the rough-textured
surface has an average roughness (Ra) of generally between about 100
nanometers (nm) and about 2.5 millimeters (mm), typically between about 5
micrometers (μm) and about 1 mm, and more typically between about 5
μm and about 250 μm. Such rough-texturing of the interior surface
can increase surface area and/or increase the fluid flow
impedance--thereby enhancing the buildup of electrical charge.

[0030] In some embodiments, the designated tubular length is
electrically-isolated from adjacent tubular segments to which it is
connected by means of a substantially-insulating coating of a second type
about at least the regions that are in mechanical contact with the
adjacent tubular segments. The coating of a second type can be of the
same or different from the coating of the first (vide supra), provided of
course that it is electrically-insulating. Such coatings of a second type
can be continuous with that of the first type provided they are of the
same material. Exemplary such coating of a second type include, but are
not limited to, material selected from the group consisting of
polytetrafluoroethylene (PTFE), polyamides (Nylon), polyimides,
polyvinylchloride (PVC), polyolefins, polyesters, and combinations
thereof.

[0031] In some such embodiments, the net, steady-state electrostatic
potential is generally at least about 5 microvolts (μV) and at most
about 500 kilovolts (kV), typically at least about 0.5 millivolts (mV) to
at most about 100 kV, and more typically at least about 2 mV to at most
about 50 kV. There is precedent for such flow-induced electrostatic
potentials; see, e.g., Paszyc et al., U.S. Pat. No. 4,223,241, issued on
Sep. 16, 1980.

[0032] The device deriving power from the harvested electrical energy is
not particularly limited. Undoubtedly, it will have some utility
downhole, pipeline, or refinery and be fabricated to withstand the
environmental conditions to which it is exposed. Notwithstanding such
aforementioned flexibility, in some embodiments the device deriving power
from the harvested electrical energy is selected from the group
consisting of one or more of the following: a pressure sensor, a
temperature sensor, a sliding sleeve, a valve, telemetry electronics,
flow meter, fluid sensing device, and combinations thereof. Additionally
or alternatively, in some embodiments, the device draws power from an
electrical storage device (e.g., one or more batteries and/or a capacitor
or bank thereof) that is, in turn, charged by the harvested electrical
energy.

[0033] In some embodiments, the substantially non-conductive
hydrocarbon-based fluid is synthetically-derived and/or comprises at
least one synthetically-derived component. By way of illustration and not
limitation, examples of potentially-suitable such synthetically-derived,
substantially non-conductive hydrocarbon-based fluids can be found in Van
Slyke, U.S. Pat. No. 6,034,037, issued Mar. 7, 2000.

[0034] In some embodiments, the electrostatic potential is generated at
least about 100 meters below the well surface (for offshore wells this
would be the sea floor), on the sea floor, on land, as part of a refinery
infrastructure. Regardless of where in the remote location the energy is
created and harvested, it can be utilized to power devices that are up to
hundreds of meters above/below or fore/aft the location at which it is
harnessed--using electrical leads of sufficient length and durability.

3. Systems of a First Type

[0035] Systems are generally consistent with implementing the methods
described above via a functional infrastructure that includes a fluid
flow (as a flowstream) as a component thereof, and as described in the
passages which follow. To an extent not inconsistent herewith, the
various aspects and details described above for methods of a first type
are applicable and suitably pertain to the systems described in this
section. The reverse is also generally true: there is generally backwards
applicability of system parameters with the methods described above.

[0036] In some embodiments, and with reference to FIGS. 2A and 2B, the
present invention is directed toward one or more systems of a first type,
such systems 200 being operable for powering devices in a remote location
through the generation of electrostatic energy locally to the device and
generally comprising: a plurality of tubular segments (e.g., 204, 205,
209) that are useful in conveying hydrocarbon-based fluids from the
remote location; at least one electrically-isolated tubular segment 204
that is electrically isolated from any adjoining segments (via insulation
207), wherein said electrically-isolated tubular segment includes a high
friction surface 214 on its interior; at least one device-bearing tubular
segment 209 comprising at least one device that can be usefully employed
(and generally requiring power to operate); at least one electrical lead
206 establishing connectivity between the at least one
electrically-isolated tubular segment 204 and the at least one
device-bearing tubular segment 209; a flow of substantially
non-conductive hydrocarbon-based fluid 217, wherein said flow is directed
through the tubular segments heading downstream or upstream from the
original tubular design; a ground electrode 235 extending into the flow,
wherein an electrical potential exists between the flow 217 and the
interior of the electrically-isolated tubular segment 204, and wherein
this electrical potential is harnessed to power at least one device in
the at least one device-bearing tubular segment 209.

[0037] Generally, such above-described plurality of tubular segments 204,
205, and 209 can range in length from less than about 1 meter to well
over 1000 meters. In some such embodiments, the length of the segments
coincides with the length of tubing joints and/or subs. In some or other
embodiments, such segments comprise a plurality of such joints and/or
subs.

[0038] In some such above-described system embodiments (of a first type),
the tubular length is operable for producing and distributing oil, gas,
or combinations thereof. The segment can be a well either on land or
offshore (including deepwater), a section of a pipeline, refinery pipe,
or any tubular within a platform or other infrastructure within the
energy sector.

[0039] In some such above-described embodiments, the electrically-isolated
tubular segment 204 exposes or otherwise presents itself to the
flowstream (flow 217) as a substantially non-conductive coating comprised
of a material selected from the group consisting of
polytetrafluoroethylene (PTFE), polyamides (Nylon), polyimides,
polyvinylchloride (PVC), polyolefins, polyesters, combinations thereof,
and non-conductive polymer compositions generally--particularly those
that lend themselves well to coatings. As mentioned in the case of the
method claims of Section 2, such coatings can have a range of thicknesses
and uniformities, and they can be multi-layered. In these or other
embodiments, the coatings can additionally or alternatively be ceramic
and/or metallic in composition. Additionally or alternatively still, in
some embodiments no coating of the electrically-isolated tubular segment
(or a portion thereof) is required.

[0040] In some such above-described embodiments, the electrically-isolated
tubular segment 204 comprises a high friction surface having an average
roughness (Ra) of generally between about 100 nm and about 2.5 mm,
typically between about 5 μm and about 1 mm, and more typically
between about 5 μm and about 250 μm. Such high friction (i.e.,
rough-textured) interior surface(s) can increase surface area and/or
increase the fluid flow impedance (via increased friction)--thereby
enhancing the buildup of electrical charge.

[0041] In some such above-described system embodiments, the at least one
device-bearing tubular segment 209 comprises one or more devices selected
from the group consisting of pressure sensors, temperature sensors,
sliding sleeves, valves, telemetry electronics, flow meters, fluid
sensing devices, and combinations thereof. Generally, such devices are
those that require power, and which would normally obtain that power via
batteries or encapsulated cable from a central location.

[0042] While in many instances the powered device(s) (being integral with,
or otherwise part of, the at least one device-bearing tubular segment
209) is in close proximity to the electrically-isolated tubular segment
204, this need not always be the case. In some such embodiments, the at
least one electrical lead can span a distance of generally up to about
1000 meters, but typically no more than about 200 meters, and more
typically no more than about 50 meters.

[0043] In some such above-described embodiments, the flow of substantially
non-conductive hydrocarbon-based fluid 217 comprises a fluid selected
from the group consisting of heptanes, diesel, crude oil, mineral oil,
and combinations thereof; such fluids, however, are merely exemplary. By
way of illustration and not limitation, additional examples of
non-conductive hydrocarbon-based (completion fluids in this case) can be
found in Pasquier et al., U.S. Pat. No. 7,858,564, issued Dec. 28, 2010;
and Patel et al., U.S. Pat. No. 5,189,012, issued on Feb. 23, 1993.

[0044] In some such above-described embodiments, the flow of substantially
non-conductive hydrocarbon-based fluid possesses a flow rate of generally
between about 1 liter/minute and about 55,000 liters/minute, typically
between about 1 liter/minute and about 10,000 liters/minute, and more
typically between about 10 liters/minute and about 5,000 liters/minute.
For any given system, the flow rate is generally seen to be proportional
to the electric potential that develops between the flow 217 and the at
least one electrically-isolated tubular segment 204. Accordingly, it is
contemplated that the electric potential could be altered to a desired
value by deliberately changing the flow rate. From an operational
perspective, flow rate would need to be sufficient for generating a
usable electrostatic potential.

[0045] In some such above-described embodiments, flow 217 is characterized
as being turbulent. While not intending to be bound by theory, turbulent
flow may be preferred for inducing electrostatic potentials in at least
some method and system embodiments of the present invention, and perhaps
particularly so for such methods and systems of a first type. See, e.g.,
Abedian et al., "Theory for Electric Charging in Turbulent Pipe Flow,"
Journal of Fluid Mechanics, vol. 120, pp. 199-217, 1982; and Abedian et
al., "Electric Currents Generated by Turbulent Flows of Liquid
Hydrocarbons in Smooth Pipes: Experiment vs. Theory," Chemical
Engineering Science, vol. 41(12), pp. 3183-3189, 1986.

[0046] In some embodiments, such above-described systems further comprise
a telemetry subsystem or means (not shown in FIGS. 2A and 2B) operable
for conveying device-generated data to the surface. While not limited
thereto, such systems are preferably wireless, with such wireless
subsystems being more fully described in Section 6 below.

4. Methods of a Second Type

[0047] Method embodiments of a second type share significant commonality
with method embodiments of a first type. The primary manner in which they
differ is in how the electrostatic potential is generated: methods of a
second type involve passing a substantially non-conductive
hydrocarbon-based fluid through a membrane. Other aspects and/or
variables of these two types of methods (and their corresponding systems)
are largely the same for each.

[0048] As mentioned previously herein and with reference to FIG. 3, in
some embodiments the present invention is directed to methods (of a
second type) of powering devices in a remote location through the
generation of electrostatic energy locally to the device, the tubular
segment being operable for the production of oil, natural gas, or
mixtures thereof, said methods generally comprising the steps of: (Step
301) flowing a substantially non-conductive hydrocarbon-based fluid, as a
flowstream, through a substantially insulating membrane; (Step 302)
generating a net, steady-state electrostatic potential between the
flowstream and said membrane, wherein the membrane comprises a plurality
of flow channels through which the substantially non-conductive
hydrocarbon-based fluid can pass, and wherein at least a majority of said
flow channels have an effective diameter of at least about 500 nm and at
most about 200 μm; (Step 303) harvesting electrical energy from the
electrostatic potential via a ground electrode in electrical contact with
the flowstream and an electrical lead in electrical contact with the
membrane; and (Step 304) using the electrical energy harvested in Step
303 to power one or more devices downhole.

[0049] In some such embodiments, the substantially non-conductive
hydrocarbon-based fluid is selected from the group consisting of (a)
completion fluid, (b) displacement fluid, (c) drilling fluid, and (d)
combinations thereof. Non-conductive hydrocarbon-based types of such
fluids are known in the art. By way of illustration and not limitation,
exemplary such fluids can be those used for methods of a first type (vide
supra).

[0050] In some embodiments, the substantially insulating membrane is
comprised of a material that is sufficiently insulating from an
operational standpoint. In some such embodiments, average pore size of
the membrane is generally between about 50 nm and about 50 mm, typically
between about 100 nm and about 1 mm, and more typically between about 250
nm and about 250 μm. In some such embodiments, the substantially
insulating membrane is comprised of a material selected from the group
consisting of polytetrafluoroethylene (PTFE), polyamides (Nylon),
polyimides, polyvinylchloride (PVC), polyolefins, polyesters, and
combinations thereof.

[0051] The downstream electrode generally is made of a material
sufficiently conductive (and durable) for it to serve as an electrode in
the manner described above. Accordingly, the material of which it is
comprised is not particularly limited. In some such embodiments, the
downstream electrode is substantially porous so as to permit flow of
fluid therethrough. In some such embodiments, average pore size of the
downstream electrode is generally between about 1 μm and about 10 cm,
typically between about 1 μm and about 5 cm, and more typically
between about 5 μm and about 5 cm.

[0052] Like the downstream electrode, the upstream electrode is generally
made of a material sufficiently conductive and durable for it to serve as
an electrode in the manner described above. Accordingly, the material of
which it is comprised is not particularly limited. In some such
embodiments, the upstream electrode is substantially porous so as to
permit flow of fluid therethrough. In some such embodiments, average pore
size of the upstream (ground) electrode is generally between about 1
μm and about 10 cm, typically between about 1 μm and about 5 cm,
and more typically between about 5 μm and about 5 cm. In some such
embodiments, where the upstream electrode takes the form of a conductive
mesh, the conductive mesh is generally of a mesh size that corresponds to
grids between about 1×1 μm and about 10×10 cm, typically
between about 5×5 μm and about 10×10 cm, and more
typically between about 5×5 μm and about 5×5 cm. The
material of which the mesh is made is not particularly limited, except
that it should possess sufficient electrical conductivity, and be
sufficiently robust, so as to be durably operational in the wellbore
environment in which it is placed.

[0053] In some such above-described embodiments, the at least one
membrane-bearing tubular segment comprises, in whole or in part, a sand
control device, filter or means. Sand control devices like sand screens
are known in the art and are ubiquitously deployed in wells throughout
the world. Care must be taken in selection of such devices or screens so
that the material makeup and dimensional attributes of the componentry
are consistent with those of the membrane-bearing tubular segment
described above. Additionally or alternatively, the at least one
membrane-bearing tubular segment can be constructed so as to also provide
for utility as a sand control device.

[0054] In some such above-described embodiments, the net, steady-state
electrostatic potential is generally at least about 5 μV and at most
about 500 kV, typically at least about 0.5 mV to at most about 100 kV,
and more typically at least about 2 mV to at most about 50 kV. Generally,
such a potential should be sufficiently great so as to
operationally-power a device remotely--even if such powering is by way of
an electrical device. Accordingly, in some such embodiments, the device
draws power from an electrical storage device that is, in turn, charged
by the harvested electrical energy.

[0055] In some such embodiments, the device deriving power from the
harvested electrical energy is selected from the group consisting of one
or more of the following: a pressure sensor, a temperature sensor, a
sliding sleeve, a valve, telemetry electronics, flow meter, fluid sensing
device, and combinations thereof

5. Systems of a Second Type

[0056] Systems of a second type are generally consistent with implementing
one or more methods (of a second type) as described above via a
functional infrastructure, and as described in the passages which follow.
Additionally, system embodiments of a second type share significant
commonality with system (and method) embodiments of a first type. The
primary manner in which they differ is in how the electrostatic potential
is generated: systems of a second type involve passing a substantially
non-conductive hydrocarbon-based fluid through a membrane assembly in a
membrane-bearing tubular segment (vide infra). Other aspects and/or
variables of these two types of systems (and their corresponding methods)
are largely the same for each.

[0057] Referring to FIGS. 4A and 4B, such systems (of a second type), for
powering devices in a remote location through the generation of
electrostatic energy locally to the device, generally comprise (as system
400) the following: a tubular length 402; a plurality of tubular segments
(e.g., 404, 405, 409) disposed within the tubular length 402, wherein
said tubular segments are useful in conveying hydrocarbon-based fluids
from a remote location; at least one membrane-bearing tubular segment 404
comprising: (i) an electrically-grounded outer upstream membrane
electrode 410, (ii) an inner downstream membrane electrode 412, (iii) a
dielectric filter membrane 411, comprising flow channels, disposed
between the inner and outer membrane electrodes wherein at least a
majority of said flow channels have an effective diameter of at least
about 500 nm and at most about 200 μm; at least one device-bearing
tubular segment 409 comprising at least one device that can be usefully
employed downhole; at least one electrical lead 406 establishing
connectivity between the inner downstream membrane electrode and the at
least one device-bearing tubular segment; a flow 417 of substantially
non-conductive hydrocarbon-based fluid, wherein said flow is directed
through the tubular segments in either a downstream or upstream direction
from tubular design; wherein an electrical potential exists between the
electrically-grounded outer upstream membrane electrode 410 and the inner
downstream membrane electrode 412, and wherein this electrical potential
is harnessed to power at least one device in the at least one
device-bearing tubular segment 409.

[0059] In some such above-described embodiments, the tubular segment is
operable for producing and distributing oil, gas, or combinations
thereof. In some embodiments, the tubular segment is a section of a
pipeline, refinery pipe, or any tubular within a platform or other
infrastructure within oil and gas.

[0060] In some such above-described embodiments, the at least one
device-bearing tubular segment 409 comprises one or more devices selected
from the group consisting of pressure sensors, temperature sensors,
valves, telemetry electronics, flow meters, fluid sensing devices, and
combinations thereof.

[0061] In some above-described embodiments, the membrane-bearing tubular
segment 404 varies in length generally from at least about 10 cm to at
most about 2500 m, typically from at least about 10 cm to at most about
1000 m, and more typically from at least about 25 cm to at most about
1000 m. In some such above-described embodiments, each of the
electrically-grounded outer upstream membrane electrode 410, the inner
downstream membrane electrode 412, and the dielectric filter membrane
411, are of substantially the same length.

[0062] In some such above-described embodiments, the dielectric filter
membrane 411 is comprised of a material selected from the group
consisting of polytetrafluoroethylene (PTFE), polyamides (Nylon),
polyimides, polyvinylchloride (PVC), polyolefins, polyesters, and
combinations thereof.

[0063] In some such above-described embodiments, one or more of the
electrically-grounded outer upstream membrane electrode 410, the inner
downstream membrane electrode, and the dielectric filter membrane, can
additionally be used for purposes other than generating power (e.g., as a
sand control device).

[0064] In some such above-described embodiments, the at least one
electrical lead 406 can span a distance within the wellbore of generally
from at least about 1 mm to at most about 10,000 m (there is generally an
upper limit that is roughly equal to the length of the well), typically
from at least about 1 cm to at most about 5,000 m, and more typically
from at least about 1 cm to at most about 1,000 m.

[0065] In some such above-described embodiments, the flow of substantially
non-conductive hydrocarbon-based fluid 402 comprises a fluid selected
from the group consisting of heptanes, diesel, crude oil, mineral oil,
combinations thereof, and the like. By way of illustration and not
limitation, exemplary such fluids can be those used for methods and
systems of a first type (vide supra).

[0066] In some such above-described embodiments, the flow of substantially
non-conductive hydrocarbon-based fluid 402 possesses a flow rate of
generally between about 1 liter/minute and about 55,000 liters/minute,
typically between about 1 liter/minute and about 10,000 liters/minute,
and more typically between about 10 liters/minute and about 5,000
liters/minute.

[0067] Analogous to many system embodiments described above, in some such
above-described embodiments electrical potential is harnessed by first
charging an electrical storage device (e.g., a battery or capacitor), and
then using said electrical storage device to power the at least one
device in the at least one device-bearing tubular segment.

[0068] In some such above-described embodiments, the system further
comprises a telemetry subsystem operable for conveying device-generated
data to a central location. While wireless telemetry techniques are
preferred, cabled means of communicating data are also contemplated.
Additionally or alternatively, in some embodiments recording devices are
employed for batch analysis at some later time, wherein the recording
devices are removed from the well and analyzed. In some embodiments, the
telemetry subsystem and/or the recording device(s) is at least partially
powered by means of electrostatic energy generated in the downhole
environment.

6. Telemetry Subsystem

[0069] The methods and systems described above optionally utilize a
telemetry means or subsystem to convey data (obtained in the at a remote
location) to the surface. While data can be recorded and later brought to
the a central location for analysis, the conveyance of such data is more
often preferably wireless in nature. Such conveyance of data can also be
via cabled transmission lines, but such cabled means generally result in
the loss of any advantages the wireless powered methods/systems afford.
Regardless, real-time data accessibility (whether wireless or cabled) is
generally preferable to batch recording and analysis because it permits
on-the-fly adaptability.

[0070] In some embodiments, where wireless transmission of data is relied
upon, such wireless transmission of data can be at least partially
provided by mud-based telemetry methods and/or acoustic transmissions.
Such techniques are known in the art and will not be described here in
further detail. For examples of such mud-based telemetry methods, see,
e.g., Kotlyar, U.S. Pat. No. 4,771,408, issued Sep. 13, 1988; and Beattie
et al., U.S. Pat. No. 6,421,298, issued Jul. 16, 2002. For examples of
wireless transmission of data (and power) up and/or down a well using
acoustic transmissions, see, e.g., Klatt, U.S. Pat. No. 4,215,426, issued
Jul. 29, 1980; and Drumbeller, U.S. Pat. No. 5,222,049, issued Jun. 22,
1993.

[0071] In some embodiments, electromagnetic (EM) transmissions of a type
described in, for example, Briles et al., U.S. Pat. No. 6,766,141, issued
Jul. 20, 2004, are used to transmit data and/or power into and out of the
cased wellbore. The downhole resonant circuits used in such methods and
systems can be integrated directly or indirectly with the one or fluid
property analyzers, so as to convey information into, and out of, the
well. See also, e.g., Coates et al., U.S. Pat. No. 7,636,052, issued Dec.
22, 2009; Thompson et al., U.S. Pat. No. 7,530,737, issued May 12, 2009;
Coates et al., U.S. Patent Appl. Pub. No. 20090031796, published Feb. 5,
2009; and Coates et al., U.S. Patent Appl. Pub. No. 20080061789,
published Mar. 13, 2008, wherein such "infinite communication" systems
and methods are additionally referred to as "INFICOMM."

7. Summary

[0072] The present invention is directed to methods for harnessing
flow-induced electrostatic energy in tubular segments for oil and gas
applications and using this energy to power electrical devices (e.g.,
flowmeters, electrically-actuated valves, etc.) in remote locations. The
present invention is also directed to corresponding systems through which
such methods are implemented.

[0073] All patents and publications referenced herein are hereby
incorporated by reference to an extent not inconsistent herewith. It will
be understood that certain of the above-described structures, functions,
and operations of the above-described embodiments are not necessary to
practice the present invention and are included in the description simply
for completeness of an exemplary embodiment or embodiments. In addition,
it will be understood that specific structures, functions, and operations
set forth in the above-described referenced patents and publications can
be practiced in conjunction with the present invention, but they are not
essential to its practice. It is therefore to be understood that the
invention may be practiced otherwise than as specifically described
without actually departing from the spirit and scope of the present
invention as defined by the appended claims.